Placebo, prozac and PLoS: significant lessons for psychopharmacology

'Nostalgic food heals for us': A qualitative exploration of experiences with nostalgia, food, and mood

ISSUE ADDRESSED

Nostalgia-the bittersweet reliving of the past-has been linked to social connection and psychological wellbeing. Although food consumption is often an intrinsically social experience, relatively little research has examined how individuals experience and understand how food consumption relates to feelings of nostalgia, food and mood.

METHODS

In the current study, semi-structured interviews were conducted with eight Australians from varying cultural backgrounds to explore their experiences with nostalgia, food and mood.

RESULTS

Reflexive thematic analysis identified three key themes from the data: (i) The bittersweet experiences of food-evoked nostalgia-individuals' descriptions of food-evoked nostalgia and how it impacted their mood both positively and negatively (ii) social connection and identity continuity-participants' description of food-evoked nostalgia and how this provides an opportunity for social connection and identity continuity throughout life, which positively influences mood, and (iii) the role and relationship of food-evoked nostalgia and mood-individual descriptions of the important role that nostalgic food plays in their life, in addition to their relationship with food, and how this impacts mood.

CONCLUSIONS

Understanding the positive component of nostalgic foods allowed individuals to bolster positive mood states with food-evoked nostalgia, increasing their quality of life. SO WHAT?: Understanding the link between food-evoked nostalgia and mood has significant implications, suggesting that negative mood states altered by nostalgic foods may result in positive mood states. Appropriate use of food-evoked nostalgia may increase the quality of life for individuals experiencing low mood states.

Position statement of the European Psychiatric Association (EPA) on the value of antidepressants in the treatment of unipolar depression

This position statement will address in an evidence-based approach some of the important issues and controversies of current drug treatment of depression such as the efficacy of antidepressants, their effect on suicidality and their place in a complex psychiatric treatment strategy including psychotherapy. The efficacy of antidepressants is clinically relevant. The highest effect size was demonstrated for severe depression. Based on responder rates and based on double-blind placebo-controlled studies, the number needed to treat (NNT) is 5–7 for acute treatment and four for maintenance treatment. Monotherapy with one drug is often not sufficient and has to be followed by other antidepressants or by comedication/augmentation therapy approaches. Generally, antidepressants reduce suicidality, but under special conditions like young age or personality disorder, they can also increase suicidality. However, under the conditions of good clinical practice, the risk–benefit relationship of treatment with antidepressants can be judged as favourable also in this respect. The capacity of psychiatrists to individualise and optimise treatment decisions in terms of ‘the right drug/treatment for the right patient’ is still restricted since currently there are no sufficient powerful clinical or biological predictors which could help to achieve this goal. There is hope that in future pharmacogenetics will contribute significantly to a personalised treatment. With regard to plasma concentration, therapeutic drug monitoring (TDM) is a useful tool to optimize plasma levels therapeutic outcome. The ideal that all steps of clinical decision-making can be based on the strict rules of evidence-based medicine is far away from reality. Clinical experience so far still has a great impact.

Severity and the Treatment of Depression: A Review of Two Controversies

Severity is an important consideration in treatment decision-making for depression. Two controversies in the treatment of depression are related to the issue of severity. First, are antidepressants only effective for severely depressed patients? Second, should the severity of depression be used as the basis for recommending medication or psychotherapy as first-line treatment? More specifically, should patients with severe depression preferentially be treated with medication? A related question is whether psychotherapy is beneficial for severely depressed patients. Some controversial articles sparked coverage in the popular press related to these questions and stimulated subsequent research on the impact of depression severity on treatment efficacy. The results of three recent large pooled analyses of patient level data indicate that the efficacy of antidepressants is not limited to the narrow band of patients who score highest on symptom severity scales. A meta-analysis of 132 controlled psychotherapy studies of more than 10,000 patients found that greater mean baseline symptom severity did not predict poorer response. A pooled analysis of individual patient data from 16 studies comparing antidepressants and cognitive behavior therapy found that severity was not associated with differential treatment outcome. These results are discussed in the context of recommendations in official treatment guidelines.

Serotonin and brain function: a tale of two receptors

Previous attempts to identify a unified theory of brain serotonin function have largely failed to achieve consensus. In this present synthesis, we integrate previous perspectives with new and older data to create a novel bipartite model centred on the view that serotonin neurotransmission enhances two distinct adaptive responses to adversity, mediated in large part by its two most prevalent and researched brain receptors: the 5-HT1A and 5-HT2A receptors. We propose that passive coping (i.e. tolerating a source of stress) is mediated by postsynaptic 5-HT1AR signalling and characterised by stress moderation. Conversely, we argue that active coping (i.e. actively addressing a source of stress) is mediated by 5-HT2AR signalling and characterised by enhanced plasticity (defined as capacity for change). We propose that 5-HT1AR-mediated stress moderation may be the brain's default response to adversity but that an improved ability to change one's situation and/or relationship to it via 5-HT2AR-mediated plasticity may also be important - and increasingly so as the level of adversity reaches a critical point. We propose that the 5-HT1AR pathway is enhanced by conventional 5-HT reuptake blocking antidepressants such as the selective serotonin reuptake inhibitors (SSRIs), whereas the 5-HT2AR pathway is enhanced by 5-HT2AR-agonist psychedelics. This bipartite model purports to explain how different drugs (SSRIs and psychedelics) that modulate the serotonergic system in different ways, can achieve complementary adaptive and potentially therapeutic outcomes.

The misleading concept of initial severity in depression clinical trials: development and results from a mathematical model

OBJECTIVE

Recently, meta-analytic studies have suggested a positive relationship between initial severity and magnitude of treatment efficacy. The aim of the current study was to develop a mathematical model to test the assumption concerning the role of initial severity in treatment response.

METHODS

A number of experimental artificial datasets were developed on the basis of three different scenarios which reflect a pre-determined effect of initial severity. They were used to test for correlations at the patient level as well as at the meta-analysis level (trial level).

RESULTS

The results suggested that in all scenarios and analyses the correlations were so high that a ceiling effect was obvious. The testing concerned changes from baseline, but not differences between arms.

CONCLUSIONS

Overall the data suggest that the question concerning the role of initial severity cannot be answered. Any allegations on such a role are based on flawed methodology and do not take into consideration the true nature of data.

Set and setting, psychedelics and the placebo response: An extra-pharmacological perspective on psychopharmacology

Placebo response theory and set and setting theory are two fields which examine how non-biological factors shape the response to therapy. Both consider factors such as expectancy, preparation and beliefs to be crucial for understanding the extra-pharmacological processes which shape the response to drugs. Yet there are also fundamental differences between the two theories. Set and setting concerns itself with response to psychoactive drugs only; placebo theory relates to all therapeutic interventions. Placebo theory is aimed at medical professionals; set and setting theory is aimed at professionals and drug users alike. Placebo theory is primarily descriptive, describing how placebo acts; set and setting theory is primarily prescriptive, educating therapists and users on how to control and optimize the effects of drugs. This paper examines how placebo theory and set and setting theory can complement and benefit each other, broadening our understanding of how non-biological factors shape response to drugs and other treatment interventions.

A mega-analysis of fixed-dose trials reveals dose-dependency and a rapid onset of action for the antidepressant effect of three selective serotonin reuptake inhibitors

The possible dose-dependency for the antidepressant effect of selective serotonin reuptake inhibitors (SSRIs) remains controversial. We believe we have conducted the first comprehensive patient-level mega-analysis exploring this issue, one incentive being to address the possibility that inclusion of low-dose arms in previous meta-analyses may have caused an underestimation of the efficacy of these drugs. All company-sponsored, acute-phase, placebo-controlled, fixed-dose trials using the Hamilton Depression Rating Scale (HDRS) and conducted to evaluate the effect of citalopram, paroxetine or sertraline in adult major depression were included (11 trials, n=2859 patients). The single-item depressed mood, which has proven a more sensitive measure to detect an antidepressant signal than the sum score of all HDRS items, was designated the primary effect parameter. Doses below or at the lower end of the usually recommended dose range (citalopram: 10-20 mg, paroxetine: 10 mg; sertraline: 50 mg) were superior to placebo but inferior to higher doses, hence confirming a dose-dependency to be at hand. In contrast, among doses above these, there was no indication of a dose-response relationship. The effect size (ES) after exclusion of suboptimal doses was of a more respectable magnitude (0.5) than that usually attributed to the antidepressant effect of the SSRIs. In conclusion, the observation that low doses are less effective than higher ones challenges the oft-cited view that the effect of the SSRIs is not dose-dependent and hence not caused by a specific, pharmacological antidepressant action. Moreover, we suggest that inclusion of suboptimal doses in previous meta-analyses has led to an underestimation of the efficacy of these drugs.

Consistent superiority of selective serotonin reuptake inhibitors over placebo in reducing depressed mood in patients with major depression

The recent questioning of the antidepressant effect of selective serotonin reuptake inhibitors (SSRIs) is partly based on the observation that approximately half of company-sponsored trials have failed to reveal a significant difference between active drug and placebo. Most of these have applied the Hamilton depression rating scale to assess symptom severity, the sum score for its 17 items (HDRS-17-sum) serving as effect parameter. In this study, we examined whether the negative outcomes of many SSRI trials may be partly caused by the use of this frequently questioned measure of response. We undertook patient-level post-hoc analyses of 18 industry-sponsored placebo-controlled trials regarding paroxetine, citalopram, sertraline or fluoxetine, and including in total 6669 adults with major depression, the aim being to assess what the outcome would have been if the single item depressed mood (rated 0-4) had been used as a measure of efficacy. In total, 32 drug-placebo comparisons were reassessed. While 18 out of 32 comparisons (56%) failed to separate active drug from placebo at week 6 with respect to reduction in HDRS-17-sum, only 3 out of 32 comparisons (9%) were negative when depressed mood was used as an effect parameter (P<0.001). The observation that 29 out of 32 comparisons detected an antidepressant signal from the tested SSRI suggests the effect of these drugs to be more consistent across trials than previously assumed. Further, the frequent use of the HDRS-17-sum as an effect parameter may have distorted the current view on the usefulness of SSRIs and hampered the development of novel antidepressants.

The public debate on psychotropic medication and changes in attitudes 1990-2011

Over the last 25 years, the appraisal of psychotropic drugs within the scientific community and their representation in the media has changed considerably. The initial optimism in the wake of the introduction of second-generation drugs has increasingly made room for a more critical evaluation of alleged advantages of these drugs. The question arises as to what extent this is reflected in similar changes in the public's attitudes towards psychiatric medication. Three representative population surveys on attitudes towards psychotropic medication were carried out in Germany in 1990 (N = 3075), 2001 (N = 2610) and 2011 (N = 1223), using the same sampling procedure, interview mode and instrument for assessing attitudes. In order to disentangle time-related effects, an age-period-cohort analysis was performed. Over the time period of 21 years, the German public's evaluation of psychotropic medication has become markedly more favourable. This change was mostly due to a period effect, i.e. concurrent influences of the social environment people are exposed to. Changes were much more pronounced in the 1990s, while over the following decade only a small, although statistically significant, increase in the favourable appraisal of medication was found. Age and birth cohort had only a minor effect on public attitudes. Our findings suggest that changes in the evaluation of the effects of psychotropic drugs within the psychiatric community and their representation in the media also affect public opinion. Given the ongoing debate about side effects and efficacy of psychiatric medication, future changes of public opinion can be expected.

Enhanced responsiveness to selective serotonin reuptake inhibitors during lactation

The physiology of mood regulation in the postpartum is poorly understood despite the fact that postpartum depression (PPD) is a common pathology. Serotonergic mechanisms and their dysfunction are widely presumed to be involved, which has led us to investigate whether lactation induces changes in central or peripheral serotonin (5-HT) systems and related affective behaviors. Brain sections from lactating (day 10 postpartum) and age-matched nulliparous (non-pregnant) C57BL/6J mice were processed for 5-HT immunohistochemistry. The total number of 5-HT immunostained cells and optical density were measured. Lactating mice exhibited lower immunoreactive 5-HT and intensity in the dorsal raphe nucleus when compared with nulliparous controls. Serum 5-HT was quantified from lactating and nulliparous mice using radioimmunoassay. Serum 5-HT concentrations were higher in lactating mice than in nulliparous controls. Affective behavior was assessed in lactating and non-lactating females ten days postpartum, as well as in nulliparous controls using the forced swim test (FST) and marble burying task (MBT). Animals were treated for the preceding five days with a selective serotonin reuptake inhibitor (SSRI, citalopram, 5mg/kg/day) or vehicle. Lactating mice exhibited a lower baseline immobility time during the FST and buried fewer marbles during the MBT as compared to nulliparous controls. Citalopram treatment changed these behaviors in lactating mice with further reductions in immobility during the FST and decreased marble burying. In contrast, the same regimen of citalopram treatment had no effect on these behaviors in either non-lactating postpartum or nulliparous females. Our findings demonstrate changes in both central and peripheral 5-HT systems associated with lactation, independent of pregnancy. They also demonstrate a significant interaction of lactation and responsiveness to SSRI treatment, which has important implications in the treatment of PPD. Although recent evidence has cast doubt on the effectiveness of SSRIs, these results support their therapeutic use in the treatment of PPD.

Is there an excess of significant findings in published studies of psychotherapy for depression?

BACKGROUND

Many studies have examined the efficacy of psychotherapy for major depressive disorder (MDD) but publication bias against null results may exist in this literature. However, to date, the presence of an excess of significant findings in this literature has not been explicitly tested.

METHOD

We used a database of 1344 articles on the psychological treatment of depression, identified through systematic search in PubMed, PsycINFO, EMBASE and the Cochrane database of randomized trials. From these we identified 149 studies eligible for inclusion that provided 212 comparisons. We tested for an excess of significant findings using the method developed by Ioannidis and Trikalinos (2007), and compared the distribution of p values in this literature with the distribution in the antidepressant literature, where publication bias is known to be operating.

RESULTS

The average statistical power to detect the effect size indicated by the meta-analysis was 49%. A total of 123 comparisons (58%) reported a statistically significant difference between treatment and control groups, but on the basis of the average power observed, we would only have expected 104 (i.e. 49%) to do so. There was therefore evidence of an excess of significance in this literature (p = 0.010). Similar results were obtained when these analyses were restricted to studies including a cognitive behavioural therapy (CBT) arm. Finally, the distribution of p values for psychotherapy studies resembled that for published antidepressant studies, where publication bias against null results has already been established.

CONCLUSIONS

The small average size of individual psychotherapy studies is only sufficient to detect large effects. Our results indicate an excess of significant findings relative to what would be expected, given the average statistical power of studies of psychotherapy for major depression.

Burning issues in the meta-analysis of pharmaceutical trials for depression

During the last decade a number of meta-analytic studies have been published and they triggered a debate on the true clinical usefulness of antidepressants. The current article comments on problems within the randomized controlled trials design, the study samples, the psychometric scales, the methods of meta-analysis, the interpretation of the results, and the reporting of conflicts of interest. Although the meta-analyses published so far agree that medication works in severe depression, they question its efficacy in mild cases. However, several methodological issues should be clarified before conclusions are definite. Different methods give different results and similar results seem to entertain a variety of interpretations. In the future it is important to address all of these problems, and to improve methodology on the basis of clinically informed choices. Otherwise, meta-analysis risks alienation from clinical reality and thus risks becoming the 21(st) century psychoanalysis.

Lessons to be learned from placebo arms in psychopharmacology trials

Large placebo effects are typically reported in clinical drug trials and evidence suggests placebo effects have increased over time. The diminishing drug-placebo difference calls into question the effectiveness of pharmacological treatments and provides a challenge to prove the effectiveness of new medications. This chapter discusses explanations for the increasing placebo effect. It highlights the contribution of spontaneous remission to the improvement in placebo groups, but focuses particularly on the role of patient and clinician expectations. Certain characteristics of the trial design can influence the formation of patient expectations and, subsequently, true placebo responses. Side effects in clinical trials may also contribute inadvertently to placebo responses. Side effects after starting medication can inform participants about their allocation to an active treatment group. Thus, they may enhance expectations of improvement and contribute to nonspecific effects in clinical trials. It is argued that specific and nonspecific effects interact in drug groups of clinical trials. This interaction influences drug-placebo differences in clinical trials (i.e., trial sensitivity). Future research should aim to identify which patients will respond best to drugs and those who may be better treated with placebos.

No role for initial severity on the efficacy of antidepressants: results of a multi-meta-analysis

INTRODUCTION

During the last decade, a number of meta-analyses questioned the clinically relevant efficacy of antidepressants. Part of the debate concerned the method used in each of these meta-analyses as well as the quality of the data set.

MATERIALS AND METHODS

The Kirsch data set was analysed with a number of different methods, and eight key questions were tackled. We fit random effects models in both Bayesian and frequentist statistical frameworks using raw mean difference and standardised mean difference scales. We also compare between-study heterogeneity estimates and produce treatment rank probabilities for all antidepressants. The role of the initial severity is further examined using meta-regression methods.

RESULTS

The results suggest that antidepressants have a standardised effect size equal to 0.34 which is lower but comparable to the effect of antipsychotics in schizophrenia and acute mania. The raw HDRS difference from placebo is 2.82 with the value of 3 included in the confidence interval (2.21-3.44). No role of initial severity was found after partially controlling for the effect of structural (mathematical) coupling. Although data are not definite, even after controlling for baseline severity, there is a strong possibility that venlafaxine is superior to fluoxetine, with the other two agents positioned in the middle. The decrease in the difference between the agent and placebo in more recent studies in comparison to older ones is attributed to baseline severity alone.

DISCUSSION

The results reported here conclude the debate on the efficacy of antidepressants and suggest that antidepressants are clearly superior to placebo. They also suggest that baseline severity cannot be utilized to dictate whether the treatment should include medication or not. Suggestions like this, proposed by guidelines or institutions (e.g. the NICE), should be considered mistaken.

Fluoxetine versus other types of pharmacotherapy for depression

BACKGROUND

Depression is common in primary care and is associated with marked personal, social and economic morbidity, thus creating significant demands on service providers. The antidepressant fluoxetine has been studied in many randomised controlled trials (RCTs) in comparison with other conventional and unconventional antidepressants. However, these studies have produced conflicting findings.Other systematic reviews have considered selective serotonin reuptake inhibitor (SSRIs) as a group which limits the applicability of the indings for fluoxetine alone. Therefore, this review intends to provide specific and clinically useful information regarding the effects of fluoxetine for depression compared with tricyclics (TCAs), SSRIs, serotonin-noradrenaline reuptake inhibitors (SNRIs), monoamineoxidase inhibitors (MAOIs) and newer agents, and other conventional and unconventional agents.

OBJECTIVES

To assess the effects of fluoxetine in comparison with all other antidepressive agents for depression in adult individuals with unipolar major depressive disorder.

SEARCH METHODS

We searched the Cochrane Collaboration Depression, Anxiety and Neurosis Review Group Controlled Trials Register (CCDANCTR)to 11May 2012. This register includes relevant RCTs from the Cochrane Central Register of Controlled Trials (CENTRAL) (all years),MEDLINE (1950 to date), EMBASE (1974 to date) and PsycINFO (1967 to date). No language restriction was applied. Reference lists of relevant papers and previous systematic reviews were handsearched. The pharmaceutical company marketing fluoxetine and experts in this field were contacted for supplemental data.

SELECTION CRITERIA

All RCTs comparing fluoxetine with any other AD (including non-conventional agents such as hypericum) for patients with unipolar major depressive disorder (regardless of the diagnostic criteria used) were included. For trials that had a cross-over design only results from the first randomisation period were considered.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by two review authors using a standard form. Responders to treatment were calculated on an intention-to-treat basis: dropouts were always included in this analysis. When data on dropouts were carried forward and included in the efficacy evaluation, they were analysed according to the primary studies; when dropouts were excluded from any assessment in the primary studies, they were considered as treatment failures. Scores from continuous outcomes were analysed by including patients with a final assessment or with the last observation carried forward. Tolerability data were analysed by calculating the proportion of patients who failed to complete the study due to any causes and due to side effects or inefficacy. For dichotomous data, odds ratios (ORs) were calculated with 95% confidence intervals (CI) using the random-effects model. Continuous data were analysed using standardised mean differences (SMD) with 95% CI.

MAIN RESULTS

A total of 171 studies were included in the analysis (24,868 participants). The included studies were undertaken between 1984 and 2012. Studies had homogenous characteristics in terms of design, intervention and outcome measures. The assessment of quality with the risk of bias tool revealed that the great majority of them failed to report methodological details, like the method of random sequence generation, the allocation concealment and blinding. Moreover, most of the included studies were sponsored by drug companies, so the potential for overestimation of treatment effect due to sponsorship bias should be considered in interpreting the results. Fluoxetine was as effective as the TCAs when considered as a group both on a dichotomous outcome (reduction of at least 50% on the Hamilton Depression Scale) (OR 0.97, 95% CI 0.77 to 1.22, 24 RCTs, 2124 participants) and a continuous outcome (mean scores at the end of the trial or change score on depression measures) (SMD 0.03, 95% CI -0.07 to 0.14, 50 RCTs, 3393 participants). On a dichotomousoutcome, fluoxetine was less effective than dothiepin or dosulepin (OR 2.13, 95% CI 1.08 to 4.20; number needed to treat (NNT) =6, 95% CI 3 to 50, 2 RCTs, 144 participants), sertraline (OR 1.37, 95% CI 1.08 to 1.74; NNT = 13, 95% CI 7 to 58, 6 RCTs, 1188 participants), mirtazapine (OR 1.46, 95% CI 1.04 to 2.04; NNT = 12, 95% CI 6 to 134, 4 RCTs, 600 participants) and venlafaxine(OR 1.29, 95% CI 1.10 to 1.51; NNT = 11, 95% CI 8 to 16, 12 RCTs, 3387 participants). On a continuous outcome, fluoxetine was more effective than ABT-200 (SMD -1.85, 95% CI -2.25 to -1.45, 1 RCT, 141 participants) and milnacipran (SMD -0.36, 95% CI-0.63 to -0.08, 2 RCTs, 213 participants); conversely, it was less effective than venlafaxine (SMD 0.10, 95% CI 0 to 0.19, 13 RCTs,3097 participants). Fluoxetine was better tolerated than TCAs considered as a group (total dropout OR 0.79, 95% CI 0.65 to 0.96;NNT = 20, 95% CI 13 to 48, 49 RCTs, 4194 participants) and was better tolerated in comparison with individual ADs, in particular amitriptyline (total dropout OR 0.62, 95% CI 0.46 to 0.85; NNT = 13, 95% CI 8 to 39, 18 RCTs, 1089 participants), and among the newer ADs ABT-200 (total dropout OR 0.18, 95% CI 0.08 to 0.39; NNT = 3, 95% CI 2 to 5, 1 RCT, 144 participants), pramipexole(total dropout OR 0.12, 95% CI 0.03 to 0.42, NNT = 3, 95% CI 2 to 5, 1 RCT, 105 participants), and reboxetine (total dropout OR0.60, 95% CI 0.44 to 0.82, NNT = 9, 95% CI 6 to 24, 4 RCTs, 764 participants).

AUTHORS' CONCLUSIONS

The present study detected differences in terms of efficacy and tolerability between fluoxetine and certain ADs, but the clinical meaning of these differences is uncertain.Moreover, the assessment of quality with the risk of bias tool showed that the great majority of included studies failed to report details on methodological procedures. Of consequence, no definitive implications can be drawn from the studies' results. The better efficacy profile of sertraline and venlafaxine (and possibly other ADs) over fluoxetine may be clinically meaningful,as already suggested by other systematic reviews. In addition to efficacy data, treatment decisions should also be based on considerations of drug toxicity, patient acceptability and cost.

The media and intellectuals' response to medical publications: the antidepressants' case

During the last decade, there was a debate concerning the true efficacy of antidepressants. Several papers were published in scientific journals, but many articles were also published in the lay press and the internet both by medical scientists and academics from other disciplines or representatives of societies or initiatives. The current paper analyzes the articles authored by three representative opinion makers: one academic in medicine, one academic in philosophical studies, and a representative of an activists' group against the use of antidepressants. All three articles share similar gaps in knowledge and understanding of the scientific data and also are driven by an 'existential-like' ideology. In our opinion, these articles have misinterpreted the scientific data, and they as such may misinform or mislead the general public and policy makers, which could have a potential impact upon public health. It seems that this line of thought represents another aspect of the stigma attached to people suffering from mental illness.

Targeting the glutamatergic system to treat major depressive disorder: rationale and progress to date

Major depressive disorder (MDD) is a severe, debilitating medical illness that affects millions of individuals worldwide. The young age of onset and chronicity of the disorder has a significant impact on the long-term disability that affected individuals face. Most existing treatments have focused on the 'monoamine hypothesis' for rational design of compounds. However, patients continue to experience low remission rates, residual subsyndromal symptoms, relapses and overall functional impairment. In this context, growing evidence suggests that the glutamatergic system is uniquely central to the neurobiology and treatment of MDD. Here, we review data supporting the involvement of the glutamatergic system in the pathophysiology of MDD, and discuss the efficacy of glutamatergic agents as novel therapeutics. Preliminary clinical evidence has been promising, particularly with regard to the N-methyl-D-aspartate (NMDA) antagonist ketamine as a 'proof-of-concept' agent. The review also highlights potential molecular and inflammatory mechanisms that may contribute to the rapid antidepressant response seen with ketamine. Because existing pharmacological treatments for MDD are often insufficient for many patients, the next generation of treatments needs to be more effective, rapid acting and better tolerated than currently available medications. There is extant evidence that the glutamatergic system holds considerable promise for developing the next generation of novel and mechanistically distinct agents for the treatment of MDD.

Serotonin circuits and anxiety: what can invertebrates teach us?

Fear, a reaction to a threatening situation, is a broadly adaptive feature crucial to the survival and reproductive fitness of individual organisms. By contrast, anxiety is an inappropriate behavioral response often to a perceived, not real, threat. Functional imaging, biochemical analysis, and lesion studies with humans have identified the HPA axis and the amygdala as key neuroanatomical regions driving both fear and anxiety. Abnormalities in these biological systems lead to misregulated fear and anxiety behaviors such as panic attacks and post-traumatic stress disorders. These behaviors are often treated by increasing serotonin levels at synapses, suggesting a role for serotonin signaling in ameliorating both fear and anxiety. Interestingly, serotonin signaling is highly conserved between mammals and invertebrates. We propose that genetically tractable invertebrate models organisms, such as Drosophila melanogaster and Caenorhabditis elegans, are ideally suited to unravel the complexity of the serotonin signaling pathways. These model systems possess well-defined neuroanatomies and robust serotonin-mediated behavior and should reveal insights into how serotonin can modulate human cognitive functions.

A critical review of the mechanism of action for the selective serotonin reuptake inhibitors: do these drugs possess anti-inflammatory properties and how relevant is this in the treatment of depression?

The selective serotonin reuptake inhibitors (SSRIs) are the most widely prescribed pharmacological treatment for depression. Since their introduction many have considered the primary mechanism by which the SSRIs produced therapeutic improvement in depression is their effect on monoaminergic signalling. In recent years, however, the credibility of the monoamine theory and the therapeutic efficacy of these compounds in the treatment of depression has been extensively criticized. In the current review the legitimacy of these criticisms is critically examined, in many instances the evidence base used to support these criticisms is found to be weak. Nevertheless, the apparent 'failure' of the monoamine theory has been of benefit in motivating research into alternative mechanisms through which the SSRIs may act. Given research demonstrating that depressive symptoms are intimately linked with disturbances in pro-inflammatory signalling, perhaps the most promising discovery has been the realisation that SSRIs posses significant anti-inflammatory properties. These recent findings are discussed and contextualised with respect to the neurogenic, neurotrophic and gluatamatergic effects that these drugs also possess.

Targeting the glutamatergic system to treat major depressive disorder: rationale and progress to date

Major depressive disorder (MDD) is a severe, debilitating medical illness that affects millions of individuals worldwide. The young age of onset and chronicity of the disorder has a significant impact on the long-term disability that affected individuals face. Most existing treatments have focused on the 'monoamine hypothesis' for rational design of compounds. However, patients continue to experience low remission rates, residual subsyndromal symptoms, relapses and overall functional impairment. In this context, growing evidence suggests that the glutamatergic system is uniquely central to the neurobiology and treatment of MDD. Here, we review data supporting the involvement of the glutamatergic system in the pathophysiology of MDD, and discuss the efficacy of glutamatergic agents as novel therapeutics. Preliminary clinical evidence has been promising, particularly with regard to the N-methyl-D-aspartate (NMDA) antagonist ketamine as a 'proof-of-concept' agent. The review also highlights potential molecular and inflammatory mechanisms that may contribute to the rapid antidepressant response seen with ketamine. Because existing pharmacological treatments for MDD are often insufficient for many patients, the next generation of treatments needs to be more effective, rapid acting and better tolerated than currently available medications. There is extant evidence that the glutamatergic system holds considerable promise for developing the next generation of novel and mechanistically distinct agents for the treatment of MDD.

How close is evidence to truth in evidence-based treatment of mental disorders?

Given the importance of the term 'evidence' in evidence-based medicine (EBM), the meaning of this term is evaluated, going back to the philosophical tradition and current meaning of the terms 'evidence' and 'truth'. Based on this, current problems in the definition of evidence and in the grading of evidence in EBM are described, taking examples from the field of psychiatry and especially pharmacopsychiatry. These problems underline that the use of the term evidence in EBM is inconsistent and inconclusive. This should be fairly stated in all EBM-related publications, especially in EBM-based guidelines, to avoid severe misunderstandings in and outside the field of psychiatry. Although EBM might have increased empirically driven rational decision-making in psychiatry/medicine, the current limitations should be carefully considered.

Antidepressant drugs and the response in the placebo group: the real problem lies in our understanding of the issue

In a recent paper, Horder and colleagues (Horder et al., 2010, J Psychopharmacol 25: 1277-1288) have suggested that the mainproblem in the Kirsch analysis is methodological. We argue that the results are similar irrespective of the method used. In our opinion the data suggest that placebo and drug effects are non-additive: antidepressants act independently of depression severity, while the placebo effect is present only in milder cases. While the response in the placebo group is due to unstable 'noise' and 'artefacts', the medication effect is reliable, valid and stable.

Onset, time course and trajectories of improvement with antidepressants

There is still considerable controversy about the onset and time course of improvement with antidepressants in the treatment of major depressive disorder. Previous studies suggested a delayed-onset hypothesis with therapeutic improvement taking several weeks, but recent meta-analyses have shown support for earlier onset of improvement within the first week or two of treatment. This paper briefly reviews the evidence, focused on antidepressant studies published since 2006, for early onset of improvement within the first 2 weeks of treatment. A PubMed electronic search was conducted with selection of relevant studies from 2007 to March 2012. With the caveat of methodological limitations, results from randomized clinical trials, meta-analyses and naturalistic studies consistently show that: (1) antidepressants in general have early onset of improvement, (2) some antidepressants, including the novel mechanism agent, agomelatine, are associated with early improvement in both core and specific symptoms such as anhedonia and sleep-wake disturbances, and (3) early improvement predicts sustained response and remission. Use of newer statistical methods to examine individual response trajectories may address some of the methodological limitations of previous studies. The predictive value of early improvement has important clinical relevance for antidepressant treatment. Measurement-based assessment for response should occur earlier and more frequently. A lack of improvement (defined as ≤20% reduction from baseline in scores on a depression rating scale) at 2-3 weeks after initiation of an antidepressant should prompt the clinician to consider a change in management.

Classification of depressive disorders

The classification of depression is well established in major diagnostic systems and operational definitions now make the diagnosis of depression reasonably reliable. However, classification and diagnosis continue to be based on clinical presentation and course and are not currently informed by aetiological or pathophysiological considerations. It is still unclear, for example, whether or not categories such as melancholic depression represent distinct subforms of illness or whether a dimensional classification based on severity can capture clinical presentation adequately and more economically. Despite these caveats, there is some evidence that distinctions between various subforms of depression can predict treatment response and this can be useful for clinical practice as well as guiding research strategies.

Solving the antidepressant efficacy question: effect sizes in major depressive disorder

BACKGROUND

Numerous reviews and meta-analyses of the antidepressant literature in major depressive disorders (MDD), both acute and maintenance, have been published, some claiming that antidepressants are mostly ineffective and others that they are mostly effective, in either acute or maintenance treatment.

OBJECTIVE

The aims of this study were to review and critique the latest and most notable antidepressant MDD studies and to conduct our own reanalysis of the US Food and Drug Administration database studies specifically analyzed by Kirsch et al.

METHODS

We gathered effect estimates of each MDD study. In our reanalysis of the acute depression studies, we corrected analyses for a statistical floor effect so that relative (instead of absolute) effect size differences were calculated. We also critiqued a recent meta-analysis of the maintenance treatment literature.

RESULTS

Our reanalysis showed that antidepressant benefit is seen not only in severe depression but also in moderate depression and confirmed a lack of benefit for antidepressants over placebo in mild depression. Relative antidepressant versus placebo benefit increased linearly from 5% in mild depression to 12% in moderate depression to 16% in severe depression. The claim that antidepressants are completely ineffective, or even harmful, in maintenance treatment studies involves unawareness of the enriched design effect, which, in that analysis, was used to analyze placebo efficacy. The same problem exists for the standard interpretation of those studies, although they do not prove antidepressant efficacy either, since they are biased in favor of antidepressants.

CONCLUSIONS

In sum, we conclude that antidepressants are effective in acute depressive episodes that are moderate to severe but are not effective in mild depression. Except for the mildest depressive episodes, correction for the statistical floor effect proves that antidepressants are effective acutely. These considerations only apply to acute depression, however. For maintenance, the long-term efficacy of antidepressants is unproven, but the data do not support the conclusion that they are harmful.

Lessons learned from placebo groups in antidepressant trials

This comprehensive review provides an overview about placebo and nocebo phenomena in antidepressant trials. Improvements in the placebo groups may partly be explained through methodological issues such as natural course of depression and regression to the mean, but also fundamentally reflect investigators' and participants' expectations. A meta-analysis by our group of 96 randomized placebo-controlled trials showed large placebo responses to antidepressant medication. Moderator analyses revealed substantially larger placebo responses in observer ratings compared with self-report. Effect sizes in observer ratings showed strong increase with publication year while this effect was not found for patients' self-ratings. This reflects the strong influence of investigators' expectations. The analysis of 'nocebo effects', e.g. adverse effects in placebo groups of antidepressant trials also confirms the impact of expectations: nocebo symptoms reflected the typical side-effect patterns expected in the drug group, with higher symptoms rates in the placebo groups of tricyclic antidepressant trials compared with placebo groups of trials testing selective serotonin reuptake inhibitors. While the placebo response seems to be similar for women and men, gender differences were found for nocebo rates. In the conclusion, we discuss potential implications for clinical trial designs and argue for interventions aimed at optimizing positive expectations of treatment benefit while minimizing the impact of adverse effects.

Clinical effectiveness, construct and assessment

BACKGROUND

In an era of contention about the efficacy of antidepressants, the concept of clinical effectiveness has surfaced as a basic tenet of real-world practice. The concept of clinical effectiveness can lead to important insights into the treatment of depression and, by acting as an organizing concept for research, can help studies better focus on obtaining information necessary to improve clinical practice.

METHODS

The limitations and strengths of efficacy and effectiveness studies in psychiatry are explored, and recent effectiveness studies in psychiatry are discussed, and their implications for re-examining treatment goals and remission.

RESULTS

Efficacy studies are invaluable for the development of new drugs, but often lack generalizability. In contrast, effectiveness studies are broader in scope and offer the potential to assess quality of life and functional change. Studies that explore the clinical effectiveness of treatments for depression can identify important treatment gaps and suggest ways to address them. Although the efficacy of an antidepressant is important, other factors such as patient adherence, safety and tolerability, and the alignment of treatment outcomes with dimensions likely to be critical to patients (quality of life and functioning) also need to be examined.

CONCLUSIONS

Antidepressant treatment, both in clinical practice and in research, should involve clinical considerations that go beyond efficacy data. Broader issues of tolerability, safety, residual symptoms, functioning, and quality of life must also be addressed. Accomplishing this objective may involve the development of new global effectiveness measures; better outcome measures; and a broader, more patient-centered orientation towards clinical care.

High frequency repetitive transcranial magnetic stimulation as an augmenting strategy in severe treatment-resistant major depression: a prospective 4-week naturalistic trial

BACKGROUND

Randomized, controlled trials (RCTs) have found repetitive transcranial magnetic stimulation (rTMS) to be effective for major depression, but its usefulness as an augmenting strategy for severe treatment-resistant depression (TRD) has yet to be firmly established.

METHODS

In a naturalistic trial, 15 chronically depressed, severely treatment-resistant patients were treated with daily high frequency (HF) rTMS over the left dorsolateral prefrontal cortex (DLPFC) for 4 weeks as an augmenting strategy. Depressive and anxious symptoms (both subjective and objective), as well as quality of life (QOL) domains were measured pre-post rTMS treatment.

RESULTS

Pre-post rTMS comparisons revealed significant reductions of both clinician-rated and selfreport depression and anxiety measures and increases in three (out of five) domains of subjective QOL (i.e., global, physical, and psychological).

LIMITATIONS

Small sample size and non-controlled design.

CONCLUSIONS

Our results suggest that HF rTMS, when used as an augmenting strategy, positively affects depressive and anxious symptoms as well as QOL in patients with severe TRD. However, further studies with larger samples and controlled designs are needed to better clarify our preliminary findings.